Recent ICT/IDOT Reports Online

The following reports from recently completed IDOT-sponsored projects are now available on ICT’s website …

R27-137: Evaluation of PCC Pavement and Structure Coring and In Situ Testing Alternatives. The objectives of this research were to evaluate core strength correction factors considering a range of pertinent factors encountered in the field and to investigate more practical core field curing practices that provide best estimates of in‐place concrete strength. The effect of core condition (including presence of embedded rebar) and core conditioning procedures (dry and wet) on the measured compressive strength of the core sample was considered. Another objective of the research was to evaluate the utility of practical non‐destructive testing methods for estimating in‐place concrete strength that could be used to reduce the amount of required coring or to provide an estimate of in situ strength for locations that cannot be cored, such as in precast prestressed beams.

R27-148: Development of Low-Water Crossing Design Guidelines for Very Low ADT Routes in Illinois. IDOT and local agencies monitor and regulate the 146,764 mi of roadway that are open to public travel in the State of Illinois. There are many old and aging bridges, culverts, and low-water crossings on rural low-volume roads that need to be replaced. The lack of design guidance for low-water crossings (LWCs) has posed difficulty for county engineers in Illinois in deciding when, where, and which type of low-water crossing to use. A study was conducted to design the guidelines for LWCs in Illinois. The study included a literature review, an LWC survey, and case studies in Illinois.

R27-155: Improving the Effectiveness of Smart Work Zone Technologies. This project evaluated the effectiveness of sensor network systems for work zone traffic estimation. A comparative analysis was performed on a work zone modeled in microsimulation and calibrated with field data from two Illinois work zones. Realistic error models were used to generate noisy measurements corresponding to Doppler radar sensors, remote traffic microwave sensors, and low-energy radar. The velocity, queue length, and travel time were estimated with three algorithms based on 1 interpolation, 2 spatio-temporal smoothing, and a 3 flow model–based Kalman filter. More than 700 sensor and algorithm configurations were evaluated, and the accuracy of the resulting traffic estimates were compared with the true traffic state from the microsimulation.

R27-162: Modeling the Performance Properties of RAS and RAP Blended Asphalt Mixes Using Chemical Compositional Information. Reclaimed asphalt pavement (RAP) and recycled asphalt shingles (RAS) can improve the sustainability of asphalt concrete (AC) as a result of the associated cost savings and environmental factors, but it is necessary to ensure that pavement performance is not compromised. To study the effects of aging and increasing asphalt binder replacement (ABR) levels, chemical characterization and rheological properties of binders from various sources were investigated. On the basis of the combined results of rheological characteristics, chemistry, and composition, it was concluded that AC prepared with high levels of ABR (more than 20%) using only RAS could have short- and long-term cracking potential because aging progresses much faster and their lifetime starts at an already critically aged condition. Asphalt concrete with high ABR content can be at an already critically aged condition immediately after production; moreover, aging progresses much faster in the binders of such mixes.